Light source for plant cultivation and plant cultivation device

ABSTRACT

A plant cultivation light source includes a substrate and a first group of light sources. The first group of light sources includes a plurality of light sources disposed on the substrate, and a light source including a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer. The plurality of light sources operates to emit lights having different wavelength bands and includes a first light source that emits first light having an area of at least about 55% compared with an area of a normalized solar spectrum, a second light source that emits second light having a wavelength for cryptochrome, and a third light source that emits third light having a wavelength for phytochrome.

CROSS-REFERENCE OF RELATED APPLICATIONS AND PRIORITY

The Present Application is a continuation of U.S. patent applicationSer. No. 16/536,222 filed Aug. 8, 2019 which claims priority to andbenefit of U.S. Provisional Application Nos. 62/717,304 filed Aug. 10,2018 and 62/824,473 filed Mar. 27, 2019, the disclosure of which areincorporated by reference in their entirety as if fully set forthherein.

BACKGROUND 1. Field of Disclosure

The present disclosure relates to a plant cultivation device and a plantcultivation method.

2. Description of the Related Art

In recent years, with the growing interest in health, there areincreasing demands for foods that are safer and healthier, such as,organic food. Typically, consumers purchase organic food at a grocerystore or a market, but consumers gradually have developed the strongdesire to self-produce organic food for their consumption. Inparticular, it may be relatively more accessible for consumers toself-produce vegetables than other food products, and therefore, thereis a large demand for a plant cultivation equipment.

In addition, interest in health leads to more attention on anti-aging,and recently, there has been a great interest in environmentallyfriendly anti-aging methods through ingestion of antioxidant present infood rather than artificial anti-aging methods through medicalprocedures and prescription medications. It is known that a build-up ofreactive oxygen species causes damage to cells and tissues and promotesaging of all tissues of human body including skin, and the antioxidanteliminates reactive oxygen species and delays body aging.Antioxidant-rich materials include vitamins, phenolic compounds, andcarotenoids. In particular, phenolic compounds are widely present inplants, are highly antioxidant, and also directly block ultraviolet raysthat promote skin aging. Plants known to have high levels ofantioxidants include legumes, berries, and vegetables. In order to meetthe demand for safer and healthier foods, there is a need to develop amethod for increasing the total phenolic compound content in plants thatare easy to grow at home.

SUMMARY

The present disclosure provides a plant having a high total phenoliccompound content and a high antioxidant capacity.

According to one or more embodiments of the present disclosure, a plantcultivation light source includes a substrate, and a first group oflight sources. The first group of light sources includes a plurality oflight sources disposed on the substrate. A light source includes a lightemitting structure including a first semiconductor layer, an activelayer, and a second semiconductor layer. The plurality of light sourcesoperates to emit lights having different wavelength bands and includes afirst light source that emits first light having an area of at leastabout 55% compared with an area of a normalized solar spectrum, a secondlight source that emits second light having a wavelength forcryptochrome, and a third light source that emits third light having awavelength for phytochrome.

In at least one variant, the first light source includes a peak having adeviation equal to or smaller than about 0.14 compared with thenormalized solar spectrum.

In another variant, the plant cultivation light source further includesa second group of light sources that have a wavelength band between 200nm and 400 nm.

In further another variant, the plant cultivation light source furtherincludes a controller coupled to the plurality of light sources in thefirst group of light sources and controlling a lighting condition and adark condition. The first group of light sources is turned off duringthe dark condition.

In another variant, a ratio of the lighting condition to the darkcondition is 1:1 to 2:1

In another variant, the plurality of light sources in the first group oflight sources further comprises an IR light source.

In another variant, the plurality of light sources further comprises awhite light emitting diode light source which irradiates at a dose ofabout 60 μmol/m²s.

In another variant, the second group of light sources is turned on oroff such that a dose of the light is equal to or greater than about 1kJ/m²s and equal to or smaller than about 14 kJ/m²s.

In another variant, the plant cultivation light source further includesa second group of light sources that have a wavelength band of between200 nm to 400 nm. The controller controls the second group light sourcesto irradiate light to a selected plant for a predetermined number ofhours prior to harvesting of the selected plant.

In another variant, a plant includes a Fabaceae Family plant, or aPoaceae Family plant.

According to one or more embodiments of the present disclosure, a plantcultivation device includes a plant cultivation light source unit, ahousing that houses a plant and the plant cultivation light source unitinstalled therein, and a controller that controls the plant cultivationlight source unit. The plant cultivation light source unit includes asubstrate, and a first group of light sources. The first group of lightsources includes a plurality of light sources disposed on the substrate.A light source includes a light emitting structure including a firstsemiconductor layer, an active layer, and a second semiconductor layer.The plurality of light sources operates to emit lights having differentwavelength bands and includes a first light source that emits firstlight having an area of at least about 55% compared with an area of anormalized solar spectrum, a second light source that emits second lighthaving a wavelength for cryptochrome, and a third light source thatemits third light having a wavelength for phytochrome.

Embodiments of the inventive concept provide a plant cultivation lightsource including a first light source emitting a first light in a firstwavelength band and a second light source emitting a second light in asecond wavelength band different from the first wavelength band. Thesecond wavelength band includes an ultraviolet light wavelength band,and the second light source is independently driven from the first lightsource to determine whether to emit the second light when the firstlight source emits the first light.

The first light source is turned on to emit the first light in alighting condition and turned off in a dark condition.

The second light source is turned on to emit the second light in thelighting condition and turned off not to emit the second light in thelighting condition.

The lighting condition and the dark condition are repeated on a 24-hourbasis.

A ratio of the lighting condition to the dark condition is 1:1 to 2:1.

The first wavelength band includes a visible light wavelength band.

The second wavelength band includes a wavelength band from about 250 nmto about 380 nm.

The second light has a peak wavelength in a range from about 270 nm toabout 300 nm.

The second light source is turned on or off such that a dose of thesecond light is equal to or greater than about 1 kJ/m²s and equal to orsmaller than about 14 kJ/m²s.

The first light source emits the first light having a relatively highintensity in a wavelength band from about 440 nm to about 495 nm and awavelength band from about 620 nm to about 750 nm.

Embodiments of the inventive concept provide a plant cultivation deviceincluding a light source unit emitting a light in a visible lightwavelength band and a light in an ultraviolet light wavelength band, ahousing provided with a plant disposed therein, the light source unitbeing installed inside the housing, and a controller controlling thelight source unit. The light source unit includes a first light sourceemitting a first light in a first wavelength band and a second lightsource emitting a second light in a second wavelength band differentfrom the first wavelength band. The second wavelength band includes theultraviolet light wavelength band, the controller controls the firstlight source to be turned on in a lighting condition and to be turnedoff in a dark condition, and the controller controls the second lightsource to be independently turned on or turned off from the first lightsource in the lighting condition.

The first wavelength band includes the visible light wavelength band.

The controller allows the dark condition different from the lightingcondition and the lighting condition to be repeated on a 24-hour basis.

The second light has a peak wavelength in a range from about 270 nm toabout 300 nm.

The controller controls a dose of the second light to become about 1kJ/m²s or more and about 14 kJ/m²s or less.

The housing provides a space in which the plant is placed andcultivated, and the first light source and the second light source areprovided on an inner surface of the housing.

The housing includes a lower case and an upper case, which are capableof being opened and closed by being engaged to each other, and the firstand second light sources are provided on an inner surface of the uppercase.

A ratio of the lighting condition to the dark condition is 1:1 to 2:1.

The controller controls the second light source to allow the secondlight source to irradiate the light to the plant for three hours beforethe plant is harvested.

The plant is a Fabaceae Family plant or a Poaceae Family plant.

According to the above, the plants having a high total phenolic compoundcontent and a high antioxidant capacity may be provided.

According to the above, the optimized growth environment depending onthe type of plants may be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other advantages of the present disclosure will becomereadily apparent by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a cross-sectional view showing a plant cultivation deviceaccording to an exemplary embodiment of the present disclosure;

FIG. 2 is a conceptual perspective view showing a cultivation deviceaccording to an exemplary embodiment of the present disclosure;

FIG. 3 is a cross-sectional view showing a plant cultivation deviceaccording to an exemplary embodiment of the present disclosure;

FIG. 4A is a plan view showing a light source unit of a cultivationdevice according to an exemplary embodiment of the present disclosure;

FIG. 4B is a view schematically showing a light emitting diode accordingto an exemplary embodiment of the present disclosure;

FIG. 5 is a block diagram showing a light source unit of a cultivationdevice according to an exemplary embodiment of the present disclosure;

FIG. 6 is a graph showing a spectrum of a light emitted from a firstlight source of a plant cultivation device when the first light sourcehas a wavelength band similar to a sunlight according to an exemplaryembodiment of the present disclosure;

FIG. 7 is a flowchart showing a plant cultivation method according to anexemplary embodiment of the present disclosure;

FIG. 8 is a flowchart showing a plant cultivation method according to anexemplary embodiment of the present disclosure;

FIG. 9 is a flowchart showing a cultivation method according to anexemplary embodiment of the present disclosure;

FIG. 10 is a graph showing a phenolic compound content as a function ofa wavelength of a second light;

FIG. 11 are photographs of barley sprouts after a second light having apeak wavelength at 285 nm is applied to the barley sprouts withdifferent doses under the same condition as in experimental example 2;

FIG. 12 is a graph showing a total phenolic compound content in thebarley sprouts after the second light having the peak wavelength at 285nm is applied to the barley sprouts with different doses under the samecondition as in experimental example 2;

FIG. 13 are photographs of wheat sprouts after the second light havingthe peak wavelength at 285 nm is applied to the wheat sprouts withdifferent doses under the same condition as in experimental example 2;and

FIG. 14 is a graph showing a total phenolic compound content in thewheat sprouts after the second light having the peak wavelength at 285nm is applied to the wheat sprouts with different doses under the samecondition as in experimental example 2.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure may be variously modified and realized in manydifferent forms, and thus specific embodiments will be exemplified inthe drawings and described in detail herein below. However, the presentdisclosure should not be limited to the specific disclosed forms, and beconstrued to include all modifications, equivalents, or replacementsincluded in the spirit and scope of the present disclosure.

Like numerals refer to like elements throughout. In the drawings, thethickness, ratio, and dimension of components are exaggerated foreffective description of the technical content. It will be understoodthat, although the terms first, second, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms are only used to distinguish oneelement, component, region, layer or section from another region, layeror section. Thus, a first element, component, region, layer or sectiondiscussed below could be termed a second element, component, region,layer or section without departing from the teachings of the presentdisclosure. As used herein, the singular forms, “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

It will be further understood that the terms “comprises” and/or“comprising”, or “includes” and/or “including”, when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. In addition, itwill be understood that when a layer, film, region, or plate is referredto as being “on” another layer, film, region, or plate, it can bedirectly on the other layer, film, region, or plate or interveninglayers, films, regions, or plates may be present. Further, it will beunderstood that when a layer, film, region, or plate is referred to asbeing formed on another layer, film, region, or plate, the formingdirection is not limited to an upward direction but includes a lateralor downward direction. Further, it will be understood that when a layer,film, region, or plate is referred to as being “under” another layer,film, region, or plate, it can be directly under the other layer, film,region, or plate or intervening layer, film, region, or plate may bepresent.

Hereinafter, exemplary embodiments of the present disclosure will beexplained in detail with reference to the accompanying drawings.

By using a plant cultivation method according to an exemplary embodimentof the present disclosure, a plant having a high total phenolic compoundcontent may be cultivated. More specifically, the plant having a hightotal phenolic compound content may be obtained by germinating a seedduring a first time, irradiating a light in a first wavelength band tothe germinated seed during a second time to grow the plant from theseed, and irradiating a light in a second wavelength band to the grownplant during a third time immediately before harvesting the plant.

Hereinafter, a plant cultivation device that may be used for cultivatingthe plant according to the plant cultivation method according to anexemplary embodiment of the present disclosure will be described.

FIG. 1 is a cross-sectional view showing a plant cultivation deviceaccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 1, the plant cultivation device 10 according to theexemplary embodiment of the present disclosure includes a main body 100,a first light source 200, and a second light source 300, and seeds 400are provided in the main body 100.

The main body 100 may include an empty space in which the seeds 400 areprovided and may be provided in a box shape that can block an externallight.

The main body 100 provides an environment in which the seeds 400 may begrown. The main body 100 may have a size such that a plurality of seeds400 may be provided and grown. The size of the main body 100 may changedepending on the use of the plant cultivation device 10. For example,the size of the main body 100 may be relatively small where the plantcultivation device 10 is used for a small-scale plant cultivation athome. Where the plant cultivation device 10 is used for commercial plantcultivation, the size of the main body 100 may be relatively large.

The main body 100 may block the light such that external light is notincident into the main body 100. A dark room environment, which isisolated from the outside, may be provided inside the main body 100.Therefore, external light may be prevented from being irradiated to theseeds 400 inside the main body 100. In particular, the main body 100 mayprevent external visible light from being irradiated to the seeds 400.However, depending on circumstances, the main body 100 may be designedto be partially open such that the main body 100 may receive theexternal light as it is.

A photocatalyst may be coated on an interior surface of the main body100. The photocatalyst receives the light provided from the first lightsource 200 and activates a photocatalytic reaction. Although theinterior space of the main body 100 is maintained in the dark roomenvironment with a lot of moisture, it is possible to prevent bacteriaor fungi from growing inside the main body 100. A photocatalyticmaterial for performing this function may include at least one selectedfrom titanium dioxide (TiO₂), zirconia (ZrO₂), tungsten oxide (WO₃),zinc oxide (ZnO), and tin oxide (SnO₂).

The main body 100 may include a water supply unit 110 and a cultureplatform 120.

The water supply unit 110 supply water to the seeds 400 provided insidethe main body 100. The water supply unit 110 may be configured to bedisposed at an upper end of the main body 100 and to spray water ontothe culture platform 120 disposed at a lower end of the main body 100.However, the configuration of the water supply unit 110 should not belimited thereto or thereby, and various types of water supply units 110may be provided depending on a shape of the main body 100 and anarrangement of the culture platform 120. For example, the water supplyunit 110 may be provided in the form of a rotating sprinkler, a mistnozzle spray, a mist generator, or the like.

One or more water supply units 110 may be provided. The number of thewater supply units 110 may be changed depending on the size of the mainbody 100. For instance, for a relatively small-sized plant cultivationdevice 10 for in-home use, one water supply unit 110 may be used sincethe size of the main body 100 is small. For a relatively large-sizedcommercial plant cultivation device 10, plural water supply units 110may be used since the size of the main body 100 is large.

The water supply unit 110 may be connected to a water tank provided inthe main body 100, or a faucet outside the main body 100. In addition,the water supply unit 110 may further include a filtration unit suchthat contaminants floating in the water are not provided to the seeds400. The filtration unit may include a filter, such as an activatedcarbon filter or a non-woven fabric filter, and thus water passingthrough the filtration unit may be purified. The filtration unit mayfurther include a light irradiation filter. The light irradiation filtermay remove germs, bacteria, fungal spores, and the like, which arepresent in water, by irradiating an ultraviolet light or the like to thewater. As the water supply unit 110 includes the above-mentionedfiltration unit, the inside of the main body 100 and the seeds 400 maynot be contaminated even when water from the water discharge unit isrecycled or rainwater or the like is directly used for the cultivation.

The water supply unit 110 may include a timer. Therefore, the watersupply unit 110 may supply water to the seeds 400 at predetermined timeintervals without a user's operation. The intervals at which water issupplied to the seeds 400 may vary depending on the type of the seeds400. For plants that require a large amount of water for growth, watermay be supplied at relatively short intervals, and for plants thatrequire less water for growth, water may be supplied at relatively longintervals.

Water provided from the water supply unit 110 may contain nutrientsnecessary for the growth of the plant. For example, the water maycontain inorganic elements necessary for the growth of plant, such asnitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium(Mg), sulfur (S), iron (Fe), manganese (Mn), copper (Cu), zinc (An),Boron (B), and molybdenum (Mo). For instance, Sachs's solution, Knop'ssolution, Hoagland solution, or Hewitt's solution may be supplied fromthe water supply unit 110.

The seeds 400 are provided on the culture platform 120. The cultureplatform 120 may support the seeds 400, and substantiallysimultaneously, may provide the nutrients to the seeds 400 to be grown.Thus, the culture platform 120 may include a culture medium required togrow the seeds 400, and the culture medium may include inorganicelements, such as nitrogen (N), phosphorus (P), potassium (K), calcium(Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), copper(Cu), zinc (Zn), Boron (B), and molybdenum (Mo).

The culture platform 120 may be provided in a shape including theculture medium and a container accommodating the culture medium. Thecontainer may have a box shape in which at least one surface, e.g., anupper surface, is removed. The culture medium and the seeds 400 may beprovided inside the container having the box shape. The seeds 400 may beprovided while being imbedded in the culture medium or placed on asurface of the culture medium depending on its type.

The culture platform 120 may have a size and a shape, which varydepending on the shape of the main body 100 and the providing manner ofthe first light source 200 and the second light source 300. The size andthe shape of the culture platform 120 may be configured to allow theseeds 400 provided on the culture platform 120 to be placed within anirradiation range of the light irradiated from the first light source200 and the second light source 300. Accordingly, even though the pluralseeds 400 are provided on the culture platform 120, the plants may growuniformly from the seeds 400 irrespective of the position of the seeds400.

The first light source 200 irradiates the light in the first wavelengthband to the seeds 400. The seeds 400 may grow by being irradiated withthe light in the first wavelength band.

The first wavelength band emitted from the first light source 200 may bea visible light wavelength band. Therefore, the seeds 400 may receivethe light in the first wavelength band, which is emitted from the firstlight source 200, and may perform photosynthesis. The plants may growfrom the seeds 400 due to the photosynthesis.

As described above, the first light source 200 may include one or morelight emitting diodes to emit the light in the visible light wavelengthband. When the first light source 200 includes one light emitting diode,the above-mentioned light emitting diode may be a light emitting diodethat emits a white light. When the first light source 200 includesplural light emitting diodes, the light emitting diodes may emit lightshaving different wavelength bands.

When the first light source 200 includes the plural light emittingdiodes, the light emitting diodes may include, for example, a lightemitting diode that emits a red light and a light emitting diode thatemits a blue light. The plants may receive the visible lights emittedfrom the above-mentioned light emitting diodes and may actively performthe photosynthesis. In this case, the red light may promote thephotosynthesis of the plants to accelerate the growth of the plants fromseeds 400, and the blue light may enhance morphogenesis and anenvironmental stress resistance of plant leaves germinated from theseeds 400. The first light source 200 may include a light emitting diodethat emits a green light. The light emitting diode emitting the greenlight may increase a photosynthetic efficiency of the plants incommunities due to its high light transmittance.

As described above, when the first light source 200 includes the lightemitting diodes that emit the lights having different wavelengths, acomposition ratio of the light emitting diodes may differ depending onthe wavelength. For example, the light emitting diodes that emit the redlight and the blue light may be provided less than the light emittingdiode that emits the green light. A ratio between the light emittingdiodes that emit the red light, the blue light, and the green light maybe determined according to the type of the seeds 400. For instance, thecomposition ratio may vary depending on a ratio of cryptochrome that isa blue light receptor to phytochrome that is a red light receptor.Alternatively, the light-emitting diodes emitting the lights ofrespective wavelength bands may be provided in the same number, and thelight-emitting diodes may be driven at different ratios depending on thetype of plants.

Since the light emitting diodes provided in the first light source 200have a waveform having a high peak at a specific wavelength, it ispossible to irradiate the lights customized to the type of the seeds400. Therefore, plants may grow faster and bigger with less power.

The first light source 200 is provided on the upper surface of the mainbody 100 and irradiates the light to the seeds 400 provided on the lowersurface of the main body 100. A position of the first light source 200on the upper surface of the main body 100 may be determined by takinginto account an irradiation angle of the light from the first lightsource 200 and a position of the culture platform 120 in which the seeds400 are provided.

The first light source 200 may emit a light in an infrared ornear-infrared wavelength band depending on circumstances.

The first light source 200 may have a waterproof structure. Accordingly,even though water splatters on the first light source 200, there is nopossibility that the first light source 200 is malfunctioning.

The second light source 300 emits the light in the second wavelengthband to the seeds 400. The second wavelength band is different from thefirst wavelength band and is in a range from about 200 nm to about 400nm. As the light in the above-mentioned wavelength is irradiated to theseeds 400, the total phenolic compound content of the seeds 400 and theplants provided from the seeds 400 may increase.

The light emitted from the second light source 300 may include a lighthaving a wavelength of about 275 nm and a light having a wavelength ofabout 295 nm. When the above-described light is irradiated to the seeds400, the total phenolic compound content and an antioxidant capacity ofthe seeds 400 and the plants may increase.

The second light source 300 may include the light emitting diode toirradiate the light. Each of the second light source 300 or the lightemitting diode included in the second light source 300 may be providedin a plural number. In this case, the light emitting diodes may emitlights having different wavelengths. For example, the second lightsource 300 may be configured to allow a portion of the second lightsources 300 or the light emitting diodes to emit the light having thewavelength of about 275 nm and the other portion of the second lightsources 300 or the light emitting diodes to emit the light having thewavelength of about 295 nm.

The second light source 300 may have a waterproof structure.Accordingly, even though the water splashes on the second light source300, the second light source 300 may not malfunction.

The seeds 400 may be provided inside the main body 100 and may grow byreceiving the water, the light in the first wavelength band, and thelight in the second wavelength band. The seeds 400 may be seeds of aFabaceae family plant or a Poaceae family plant. For example, the seeds400 may be seeds of soybeans, mung beans, peas, alfalfa, wheat, barley,rice, bamboo, oat, millet, sorghum, sugarcane, and corn. In the case ofthe seeds of the Fabaceae family plant or the Poaceae family plant, whenthe seeds of the Fabaceae family plant or the Poaceae family plant arecultivated by the plant cultivation method according to an exemplaryembodiment of the present disclosure, it was checked that the totalphenolic compound content or the antioxidant capacity was very high.This will be described in detail later.

The seeds 400 receive the light irradiated from the second light source300 during the cultivation. The light irradiated from the second lightsource 300 increases the total phenolic compound content of plants grownfrom the seeds 400. In detail, the light irradiated from the secondlight source 300 and having the second wavelength band activatessecondary metabolite biosynthesis of plants to increase the totalphenolic compound content and the antioxidant capacity. When the lightin the second wavelength band is irradiated to plants, the light havingthe above-described wavelength causes mechanisms, such as a DNA-damagingeffect on plant cells and a generation of reactive oxygen species,resulting in serious cell and tissue damage. The plants promote theproduction of the secondary metabolites that are capable of absorbingthe light or eliminating the reactive oxygen species to protect thetissue cells.

For example, when the light is provided to the plants grown from theseeds 400, an enzyme such as phenylalanine ammonia-lyase, which isinvolved in the biosynthesis of the secondary metabolites having theabove-mentioned activity, is activated. Thus, the biosynthesis of thephenolic compounds is promoted, and as a result, the antioxidantcapacity of the plants increases, and the tissue damage caused by thelight is alleviated.

The antioxidant contained in the plants provided by the above-describedmethod may be phenolic compounds, vitamins, and carotenoids.

In addition, the phenolic compounds may include, but are not limited to,flavonoids, phenolic acids, polyphenols, stilbenoids, hydrocinnamicacids, coumaric acids, and the like.

According to the exemplary embodiment of the present disclosure, as theplant cultivation device 10 that includes the main body 100, the firstlight source 200, and the second light source 300 is provided, plantswith a high total phenolic compound content and a high antioxidantcapacity may be cultivated without the influence of externalenvironment. In addition, the first wavelength band and the secondwavelength band, which are respectively emitted from the first lightsource 200 and the second light source 300, are configured by takinginto account the type of the seeds 400, and thus an optimized growthenvironment for each plant may be provided.

FIG. 2 is a conceptual perspective view showing a plant cultivationdevice according to an exemplary embodiment of the present disclosure.

Referring to FIG. 2, the plant cultivation device 10 according to theexemplary embodiment of the present disclosure includes a main body 100having an inner space capable of growing plant sprouts and a first lightsource unit 200 provided in the main body 100 to emit a light.

The main body 100 provides an empty space therein within which plantseeds may be provided and may be grown into the plant sprouts. The mainbody 100 may be provided in a box shape that can block an externallight. In the exemplary embodiment of the present disclosure, the mainbody 100 may include a lower case 101 opened upward and an upper case103 opened downward. The lower case 101 and the upper case 103 may becoupled to each other to form the box shape that blocks the externallight.

The lower case 101 includes a bottom portion and a sidewall portionextending upward from the bottom portion. The upper case 103 includes acover portion and a sidewall portion extending downward from the coverportion. The sidewall portions of the lower case 101 and the upper case103 may have structures that are engaged with each other. The lower case101 and the upper case 103 may be coupled to each other, or separatedfrom each other depending on a user's need, and thus a user may open orclose the main body 100.

The main body 100 may be provided in various shapes. For example, themain body 100 may have a substantially rectangular parallelepiped shapeor may have a cylindrical shape. However, the shape of the main body 100should not be limited thereto or thereby, and the main body 100 may beprovided in other shapes.

In the present exemplary embodiment, the space inside the main body 100may be provided as one space. However, this is for the convenience ofexplanation, and the space inside the main body 100 may be divided intoa plurality of compartments. That is, partition walls may be provided inthe main body 100 to divide the space inside the main body 100 into thecompartments.

The first light source unit 200 provides the light to the plant sproutsin the space of the main body 100. The first light source unit 200 isdisposed on an inner surface of the upper case 103 or the lower case101. In the exemplary embodiment of the present disclosure, the firstlight source unit 200 may be disposed on the cover portion of the uppercase 103. In the present exemplary embodiment, the first light sourceunit 200 disposed on an inner surface of the cover portion of the uppercase 103 is shown; however, it is not limited thereto or thereby. Forexample, according to another embodiment of the present disclosure, thefirst light source unit 200 may be disposed on the sidewall portion ofthe upper case 103. As another example, according to another embodimentof the present disclosure, the first light source unit 200 may bedisposed on the sidewall portion of the lower case 101, e.g., on anupper end of the sidewall portion. As another example, according toanother embodiment of the present disclosure, the first light sourceunit 200 may be disposed on at least one of the cover portion of theupper case 103, the sidewall portion of the upper case 103, and thesidewall portion of the lower case 101.

A culture platform 130 may be provided in the space of the main body 100to cultivate the plant easily, for example, for facilitating ahydroponic culture. The culture platform 130 may include a plate-shapedplate 131 disposed at a position spaced apart upward from the bottomportion of the main body 100. A through-hole 133 with a uniform size maybe provided through the plate 131. The culture platform 130 may beprovided to allow the seeds of the Poaceae family plant to be grown onan upper surface of the plate 131 and may include a plurality ofthrough-holes 133 to allow water supplied thereto to be drained when thewater is supplied in a state where the seeds of the Poaceae family plantare placed on the upper surface thereof. The through-hole 133 may beprovided in a size such that the seeds of the Poaceae family plant donot slip through. For example, the through-hole 133 may have a diametersmaller than the seed of the Poaceae family plant. A space between theculture platform 130 and the bottom portion of the lower case 101 mayserve as a water tank in which the drained water is stored. Accordingly,the water drained downward through the through-hole 133 of the cultureplatform 130 may be stored between the bottom portion of the lower case101 and the culture platform 130.

According to the exemplary embodiment of the present disclosure, thesprouts of the Poaceae family plant may also be cultivated by methodsother than hydroponic culture. In this case, water, a culture medium,and soil may be provided in the space of the main body 100 to supplywater and/or nutrients necessary for the sprouts of the Poaceae familyplant, and the main body 100 may serve as a container. The culturemedium or soil may contain the nutrients for the seeds to grow, such aspotassium (K), calcium (Ca), magnesium (Mg), sodium (Na), and iron (Fe).The seeds may be provided while being imbedded in the culture medium orplaced on a surface of the culture medium depending on its type.

The culture platform 130 may have a size and a shape, which varydepending on the shape of the main body 100 and how a first light source201 and a second light source 202 are arranged. The size and the shapeof the culture platform 130 may be configured to allow the seedsprovided on the culture platform 130 to be placed within an irradiationrange of the light irradiated from the first light source 201 and thesecond light source 203.

The main body 100 may include a water supply unit disposed therein tosupply water to the seeds. The water supply unit may be configured to bedisposed at an upper end of the main body 100, e.g., on the innersurface of the cover portion of the upper case 103, and to spray wateronto the culture platform 130. However, the configuration of the watersupply unit should not be limited thereto or thereby, and theconfiguration of the water supply unit may vary depending on the shapeof the main body 100 and the arrangement of the culture platform 130. Inaddition, users may directly supply water into the main body 100 withouta separate water supply unit. In the above descriptions, the simpleplant cultivation device according to the exemplary embodiment of thepresent disclosure has been described. However, since the plantcultivation device according to the embodiment of the present disclosuremay be used for commercial plant production, other forms of plantcultivation device for use in commercial plant production will bedescribed in detail.

FIG. 3 is a cross-sectional view showing a plant cultivation deviceaccording to an exemplary embodiment of the present disclosure.

The plant cultivation device 10 according to the exemplary embodimentmay be operated as a plant production factory. Accordingly, the plantcultivation device 10 may include a plurality of culture platforms 120,a first light source unit 200, and a second light source unit 300.

As shown in figures, the culture platforms 120, the first light sourceunit 200, and the second light source unit 300 may define severalcompartments. Therefore, a main body 100 may be provided in a structurethat includes several compartments.

The several compartments included in the main body 100 may be operatedindependently of each other. For example, the first light source unit200 provided in some compartments may emit more blue light than redlight, and the first light source unit 200 provided in othercompartments may emit more red light than blue light. In addition, eachcompartment of the main body 100 may be operated differently in terms oftime. For example, the first light source unit 200 may emit the light inthe first wavelength band to grow plants 401 in some compartments, andthe second light source unit 300 may emit the light in the secondwavelength band to increase a total phenolic compound content in theplants 401 in other compartments.

Each compartment included in the main body 100 may be configured to forma closed dark room, and thus each compartment may be independentlyoperated as described above. Therefore, the light(s) emitted from thefirst light source unit 200 and/or the second light source unit 300 andprovided to an arbitrary compartment may not exert an influence on othercompartments.

The culture platform 120 provided in the main body 100 may includedifferent culture media from each other depending on the type of theplants 401. Thus, it is possible to provide the growth environmentcustomized to the type of the plants 401. In addition, the cultureplatform 120 may be separated from the main body 100. Accordingly, whenthe plants 401 growing on some culture platforms 120 reach a harvestingstage, users may separate only the culture platform 120 on which theplants 401 completely grown are provided from the main body 100 withoutaffecting the entire plant cultivation device 10.

The main body 100 may further include a water supply unit, and the watersupply unit is provided on a surface at which the main body 100 makescontact with the culture platform 120 to directly supply the water tothe culture medium included in the culture platform 120. Therefore,different from the spray-type water supply unit, water may be suppliedwithout affecting other culture platforms 120 even when the cultureplatforms 120 are stacked one on another.

The first light source unit 200 may be provided in a plural numberaccording to a shape of the culture platform 120. As described above,the first light source unit 200 may include a plurality of lightemitting diodes that emits lights having different wavelengths, and thelight emitting diodes may be provided in the same ratio or differentratios in the first light source unit 200. When the light emittingdiodes that emit the lights having the different wavelengths areprovided in the same ratio in the first light source unit 200, the firstwavelength band may be controlled by a controller to correspond to thetype of the plants 401. Therefore, the growth environment suitable forthe type of the plants 401 may be provided.

Two or more of the second light source unit 300 may be provided. Thesecond light sources 300 may be provided in different compartments fromeach other in the main body 100 and may be independently operated.Accordingly, the light in the second wavelength band may be irradiatedto only the completely grown plants 401 in a phase where the totalphenolic compound content is to be increased.

As described above, the plural plants 401 may be substantiallysimultaneously cultivated using the plant cultivation device 10, and thegrowth environment suitable for the type of the plants 401 may beindependently provided. Accordingly, the plants 401 different from eachother may be substantially simultaneously cultivated by using the plantcultivation device 10, and the cultivated plants 401 have a high totalphenolic compound content.

Referring to FIGS. 4A, 4B, and 5, the first light source unit 200includes the first light source 201 that emits the light having avisible light wavelength band and the second light source 203 thatprovides the light having an ultraviolet wavelength band to the plantsprouts.

The first light source 201 and the second light source 203 may bedisposed on a substrate 20. The substrate 20 may be a printed circuitboard on which wirings and circuits are formed to allow the first lightsource 201 and the second light source 203 to be directly mountedthereon, however, the substrate 20 should not be limited to the printedcircuit board. The shape and structure of the substrate 20 should not beparticularly limited as long as the first light source 201 and thesecond light source 203 are mounted on the substrate, and the substrate20 may be omitted. For example, the upper case of the housing describedlater may be used as the substrate, and the first light source 201 andthe second light source 203 may be disposed on the upper case.

The first light source 201 irradiates a light in a first wavelength bandto the seeds. The first wavelength band may be a visible lightwavelength band, and the seeds may grow by receiving the light in thefirst wavelength band. The seeds may receive the light in the firstwavelength band, which is emitted from the first light source 201, andmay perform photosynthesis.

FIG. 4B is a view schematically showing a light emitting diode accordingto an exemplary embodiment of the present disclosure.

Referring to FIG. 4B, the light emitting diode may include a lightemitting structure including a first semiconductor layer 2013, an activelayer 2015, and a second semiconductor layer 2017, a first electrode2011 connected to the light emitting structure, and a second electrode2019 connected to the light emitting structure.

The first semiconductor layer 2013 is a semiconductor layer doped with afirst conductive type dopant. The first conductive type dopant may be ap-type dopant. The first conductive type dopant may be Mg, Zn, Ca, Sr,or Ba. In the exemplary embodiment of the present disclosure, the firstsemiconductor layer 2013 may include a nitride-based semiconductormaterial. In the exemplary embodiment of the present disclosure, thematerial for the first semiconductor layer 2013 may be GaN, AlN, AlGaN,InGaN, InN, InAlGaN, or AlInN.

The active layer 2015 is disposed on the first semiconductor layer 2013and corresponds to a light emitting layer. The active layer 2015 is alayer in which electrons (or holes) injected through the firstsemiconductor layer 2013 and holes (or electrons) injected through thesecond semiconductor layer 2017 meet each other and emit a light due toa band gap difference of an energy band according to a material forforming the active layer 2015.

The active layer 2015 may be implemented with a compound semiconductor.The active layer 2015 may be implemented with, for example, at least oneof compound semiconductors of Groups III-V or II-VI.

The second semiconductor layer 2017 is disposed on the active layer2015. The second semiconductor layer 2017 is a semiconductor layer dopedwith a second conductive type dopant having a polarity opposite to thatof the first conductive type dopant. The second conductive type dopantmay be an n-type dopant, and the second conductive type dopant may be,for example, Si, Ge, Se, Te, O, or C.

In the exemplary embodiment of the present disclosure, the secondsemiconductor layer 2017 may include a nitride-based semiconductormaterial. The material for the second semiconductor layer 2017 may beGaN, AlN, AlGaN, InGaN, InN, InAlGaN, or AlInN.

The first electrode 2011 and the second electrode 2019 may be providedin various forms to be respectively connected to the first semiconductorlayer 2013 and the second semiconductor layer 2017. In the presentexemplary embodiment, the first electrode 2011 is disposed under thefirst semiconductor layer 2013, and the second electrode 2019 isdisposed on the second semiconductor 2017, however, they should not belimited thereto or thereby. In the exemplary embodiment of the presentdisclosure, the first electrode 2011 and the second electrode 2019 mayinclude various metals, such as Al, Ti, Cr, Ni, Au, Ag, Sn, W, Cu, oralloys thereof. Each of the first electrode 2011 and the secondelectrode 2019 may have a single-layer or multi-layer structure.

In the exemplary embodiment of the present disclosure, the lightemitting diode is described as a vertical type light emitting diode,however, the light emitting diode does not necessarily need to be thevertical type and may be provided in other types as long as itcorresponds to the concept of the present invention.

According to the exemplary embodiment of the present disclosure, thefollowing effects may be obtained by using the light emitting diodeinstead of a conventional lamp as a light source for applying the lightto a sample.

When the light emitting diode according to the exemplary embodiment ofthe present disclosure is used as the first light source 201 and/or thesecond light source 203, a light having a specific wavelength may beprovided to the plants compared with a light emitted from theconventional lamp (e.g., a conventional UV lamp). The light emitted fromthe conventional lamp has a broad spectrum in a wide area compared withthe light emitted from the light emitting diode. Accordingly, in thecase of the conventional UV lamp, it is not easy to separate only thelight of some bands from the wavelength band of the emitted light. Incontrast, the light emitted from the light emitting diode has a sharppeak at a specific wavelength and provides a light of a specificwavelength having a very narrow full-width-half-maximum in comparisonwith the light from the conventional lamp. Therefore, it is easy toselect the light of the specific wavelength, and only the light of theselected specific wavelength may be provided to the sample.

In addition, in the case of the conventional lamp, it is difficult toprecisely limit an amount of the light while providing the light to asample, but in the case of the light emitting diode, it is possible toprecisely limit the amount of the light while providing the light.Further, in the case of the conventional lamp, it is difficult toprecisely limit the amount of the light, and thus, an irradiation timemay be set in a wide range. However, in the case of the light emittingdiode, the light may be provided to the sample within a definite timefor a relatively short time.

As described above, in the case of the conventional lamp, it isdifficult to clearly determine the amount of the light due to therelatively wide wavelength, the wide range of light amount, and the widerange of irradiation time. In contrast, in the case of the lightemitting diode, a clear light dose may be provided due to the relativelynarrow range of wavelength, the narrow range of light amount, and thenarrow range of irradiation time.

In addition, in the case of the conventional lamp, it takes a long timeto reach a maximum amount of light after turning on the power. Incontrast, when using light emitting diodes, it reaches the maximumamount of light with substantially no warm-up time after turning on thepower. Thus, in the case of the light emitting diode light source, theirradiation time of the light may be accurately controlled when theplants are irradiated with a light of a specific wavelength.

In the exemplary embodiment of the present disclosure, the first lightsource may emit a light having a wavelength band similar to that ofsunlight so that the seeds grow as much as possible.

FIG. 6 is a graph showing a spectrum of the light emitted from the firstlight source of the cultivation device when the first light source hasthe wavelength band similar to that of the sunlight according to anexemplary embodiment of the present disclosure. Referring to FIG. 6, thefirst light source may emit the light in the wavelength band from about380 nm to about 750 nm. Most of the light may be in the visible lightwavelength band. That is, the first light source corresponds to a lightsource that emits a white light.

The first light source may include one or more light emitting diodes toemit the light in the visible light wavelength band. In the drawings,one first light source is shown; however, the number of the first lightsources should not be limited to one. The plural light emitting diodesmay be provided. When the first light source includes the plural lightemitting diodes, the light emitting diodes may emit lights having thesame wavelength band, or may emit lights having different wavelengthbands from each other. For example, the plural light emitting diodes mayinclude at least one of a light emitting diode that emits a red light, alight emitting diode that emits a blue light, and a light emitting diodethat emits a green light.

In the exemplary embodiment of the present disclosure, when the firstlight source includes the light emitting diodes that emit the lightshaving different wavelengths, a composition ratio of the light emittingdiodes may differ depending on the wavelength. For example, the lightemitting diodes that emit the red light may be provided less than thelight emitting diodes that emit the blue light or the green light, and alight emitting diode that emits the white light may be provided.

In addition, the first light source in the present exemplary embodimentmay provide energy required for plant growth. More specifically, thefirst light source may provide the energy in the form of light for theplants to perform photosynthesis and grow. The wavelength of the lightprovided by the first light source may thus be determined by taking intoaccount an absorption rate of a photoreceptor of the plants. Forexample, the first light source may emit a light having a relativelyhigh light intensity in a blue light wavelength band (about 440 nm toabout 495 nm) and a red light wavelength band (about 620 nm to about 750nm), which are mainly used for the plant photosynthesis.

However, the light emission form of the first light source should not belimited to the above-described embodiment, and, in some cases, the lightemitted from the first light source may have a spectrum similar to thatof the sunlight, in which the lights of the entire range of wavelengthbands are uniformly mixed. However, the first light source according tothe exemplary embodiment of the present disclosure differs from thesunlight in that the first light source emits the light except for mostof the light corresponding to the ultraviolet wavelength band. The firstlight source according to the exemplary embodiment of the presentdisclosure may emit the light having the wavelength band of about 380 nmto about 780 nm substantially corresponding to the entire wavelengthband of the visible light. In the exemplary embodiment of the presentdisclosure, the expression “similar to sunlight” means a case where anoverlapping area is equal to or greater than a predetermined value incomparison with a conventional art and a deviation (a degree ofdeviation with respect to a peak of the solar spectrum) of the peak fromthe solar spectrum is also equal to or smaller than a predeterminedvalue based on a normalized solar spectrum. For example, in theexemplary embodiment of the present disclosure, the first light sourcemay emit the light having an area of at least about 55% when comparedwith an area of the normalized solar spectrum, and a peak of a firstlight may have the deviation equal to or smaller than about 0.14 whencompared with the normalized solar spectrum. As described above, sincethe first light source has the spectrum similar to that of the sunlight,the plant sprouts may grow well through efficient photosynthesis.

Referring to FIGS. 4A, 4B, and 5 again, the second light source 203 mayemit a second light having a second wavelength band to the seeds.

The second wavelength band may be different from the first wavelengthband and may be an ultraviolet wavelength band of about 250 nm to about380 nm. In the exemplary embodiment of the present disclosure, thesecond light may correspond to at least one of a UV-A, a UV-B, and aUV-C. In the exemplary embodiment of the present disclosure, the secondlight source 203 may emit at least one light among lights having peakwavelengths of about 255 nm, about 275 nm, about 285 nm, about 295 nm,about 315 nm, about 335 nm, and about 365 nm.

In the exemplary embodiment of the present disclosure, the second lightsource 203 may emit the light in the wavelength band of about 270 nm toabout 300 nm and may emit one of the lights having the peak wavelengthsof about, 275 nm, about 285 nm, and about 295 nm. In the exemplaryembodiment of the present disclosure, the second light source 203 mayemit the light in the wavelength band of about 285 nm.

The second light source 203 may include one or more light emittingdiodes to emit the light in the ultraviolet wavelength band. In thedrawings, one first light source 31 is shown; however, it should not belimited to one. The plural light emitting diodes may be provided. In thecase where the second light source 203 includes the plural lightemitting diodes, the light emitting diodes may emit lights having thesame wavelength band or may emit lights having different wavelengthbands from each other. For example, the second light source 203 may beconfigured to allow some second light sources 33 or light emittingdiodes to emit the light having the wavelength of about 275 nm and someother second light sources 33 or light emitting diodes to emit the lighthaving the wavelength of about 285 nm.

The second light source 203 is to increase an antioxidant content in theplant sprout by irradiating the light in the ultraviolet wavelengthband. The antioxidant content in the seeds and the plant sprouts mayincrease by irradiating the light emitted by the second light source 203to the plant for a predetermined time at a predetermined intensity.

In the exemplary embodiment of the present disclosure, a light sourcethat emits a light in an infrared or near-infrared wavelength band mayfurther be provided in addition to the first light source 201 and/or thesecond light source 203. Alternatively, the first light source 201 mayemit the light in the infrared or near-infrared wavelength band inaddition to the light in the visible light wavelength band.

In the exemplary embodiment of the present disclosure, a controller 220for controlling whether to operate or not the first light source 201 andthe second light source 203 may be connected to the first light source201 and/or the second light source 203 by wire or wirelessly.

The controller 220 is connected to a power supply unit 230 that suppliesa power to the controller 220. The power supply unit 230 may beconnected to the light source unit 30 via the controller 220 or may bedirectly connected to the light source unit 30 to supply the power tothe light source unit 30.

The controller 220 may control ON/OFF of the first light source 201and/or the second light source 203 such that the first light source 201and/or the second light source 203 emit the lights for a predetermineperiod at a predetermined intensity. The first light source 201 and thesecond light source 203 may be individually and independently operatedto cultivate the plant sprouts to contain the antioxidant as much aspossible.

The controller 220 may independently control the first light source 201and the second light source 203 so that the first light and/or thesecond light are emitted at a predetermined frequency of emission in apredetermined wavelength band. In addition, when the first light source201 and/or the second light source 203 include the plural light emittingdiodes, the individual light emitting diodes may be independentlycontrolled.

In the exemplary embodiment of the present disclosure, in a case wherethe housing is divided into a plurality of compartments, the first lightsources 201 and/or the second light sources 203 may be provided invarious numbers in the compartments. In this case, the controller 220may independently control the first light sources 201 and/or the secondlight sources 203 corresponding to respective compartments such that thelight is irradiated in various ways in the plurality of compartments.For example, the light in the first wavelength band may be irradiatedfrom the first light source 201 to grow the plant sprouts in somecompartments, and the light in the second wavelength band may beirradiated from the second light source 203 to increase the antioxidantcontent in other compartments. Each compartment included in the housingmay form a closed dark room to be independently operated. Therefore, thelight emitted from the first light source 201 and/or the second lightsource 203 provided in an arbitrary compartment may not exert aninfluence on other compartments.

In the exemplary embodiment of the present disclosure, the controller220 may control whether to operate or not the first light source 201 andthe second light source 203 according to a preset process or accordingto a user's input. For example, the controller 220 may not operate thefirst and second light sources 31 and 33 for a first time, may operatethe first light source 201 for a second time, and may operate the secondlight source 203 for a third time in sequence. In addition, the user maymanually input a length of the first time, the second time, and thethird time and an intensity of the light of the first light source 201and/or the second light source 203.

According to the exemplary embodiment of the present disclosure, thecontroller 220 may be connected to the water supply unit in addition tothe first light source 201 and/or the second light source 203. Thecontroller 220 may control an amount of the water supplied through thewater supply unit and a time during which the water is supplied.

For example, the water supply unit may supply water to the seeds atpredetermined time intervals without a user's operation. The intervalsat which the water is supplied to the seeds may vary depending on thetype of the seeds. In the case of plants that require a lot of water forgrowth, water may be supplied at relatively short intervals, and in thecase of plants that require less water for growth, water may be suppliedat relatively long intervals.

In the exemplary embodiment of the present disclosure, the seedsprovided in a culture platform may be the seeds of the Poaceae familyplant. For example, the seeds provided in the culture platform may bebarley, wheat, oat, rice, millet, sorghum, sugarcane, and maize.However, the type of the seeds should not be limited thereto or thereby.

According to the exemplary embodiment of the present disclosure, as theabove-described plant cultivation device is provided, the plant havingthe high antioxidant content may be obtained without being influenced bythe external environment.

The plant cultivation device according to the exemplary embodiment ofthe present disclosure may be operated in the form of a large factory toobtain a large amount of plants, that is, a plant-production facility,as well as a cultivation device for home use or personal use tocultivate a relatively small amount of plants. Accordingly, the plantcultivation device may include a plurality of culture platforms, thefirst light source, the second light source, and the water supply unit(not shown).

In the exemplary embodiment of the present disclosure, various sensors,e.g., a temperature sensor, a humidity sensor, and a light intensitysensor, may be additionally disposed in the plant cultivation deviceoperated in the plant-production facility, and the controller 220 mayreceive data from the sensors and may control the first and second lightsources and the water supply device as a whole or individually. Thecultivation device equipped with the plant cultivation system maytransmit and receive data either directly or from a remote location bywired, wireless, or internet connection and may display data from thevarious sensors, the first and second light sources, and the watersupply unit through a separate display. The user may instruct thecontroller 220 to implement optimal conditions after reviewing suchdata.

As described above, the plants with improved immune system may be easilygrown in large quantities by using the plant cultivation deviceaccording to the exemplary embodiment of the present disclosure. Inaddition, when using the plant cultivation device according to theexemplary embodiment of the present disclosure, various types of plantsmay be grown simultaneously, and a growing environment suitable for thetype of plants may be independently provided. Thus, when using the plantcultivation device according to the exemplary embodiment of the presentdisclosure, different types of plants may be grown simultaneously, andthus the cultivated plants have the high immunity.

In the above descriptions, the plant cultivation device according to theexemplary embodiment of the present disclosure has been described.Hereinafter, a plant cultivation method performed using the plantcultivation device will be described in detail.

FIG. 7 is a flowchart showing a plant cultivation method according to anexemplary embodiment of the present disclosure.

Referring to FIG. 7, the seed provided in the main body is germinatedduring a first time P1 (S100).

The germination means a process by which a plant grows from a seed, anda seedling means a young plant grown from the germinated seed.

Since a germination condition may vary depending on the type of theseed, the inside of the main body may be set to match the germinationcondition of the seed during the first time P1. For example, in the caseof a light-germinated seed requiring light for its germination, thelight may be irradiated to the seed using the first light source duringthe first time P1. In the case of the light-germinated seed, the firstlight source may irradiate the red light to the seed. The red lightconverts the phythochromes in the seed from a red light absorbing form(Pr) to a near-infrared light absorbing form (Pfr), and thenear-infrared light absorbing form phytochrome (Pfr) decreases abscisicacid content which leads to seed dormancy while increasing gibberellincontent. Accordingly, the germination may be promoted by the red light.On the contrary, in the case of a dark-germinated seed that does notrequire light for its germination, the inside of the main body may bemaintained in the dark room during the first time P1.

In the germination stage, an amount of water supplied by the watersupply unit may increase. This is because the seed is required to absorbsufficient water to allow a cell metabolic reactions to begin and togrow. Therefore, the supply of the water may be concentrated in thegermination stage such that the seed absorbs enough water or the seedstarts imbibition.

In the germination stage, the inside of the main body may be maintainedat a temperature of about 20 Celsius degrees to about 30 Celsiusdegrees. The germination of the seed may be promoted in the abovetemperature range. The main body may include various types oftemperature control units to maintain the above temperature.

The first time P1 during which the germination process is performed mayvary depending on the type of plant. Accordingly, users, or thecontroller may control the first time P1 differently depending on thetype of plant that is to be cultivated.

Then, the light in the first wavelength band is irradiated to thegerminated seed (S200).

The light in the first wavelength band may be irradiated to thegerminated seed during a second time. As the light in the firstwavelength band is irradiated to the germinated seed, the plant may begrown from the seed. The first wavelength band may be the visible lightwavelength band; however, depending on circumstances, the firstwavelength band may include the near-infrared wavelength band. The firstwavelength band may differ depending on the type of the plant that is tobe cultivated.

The light in the first wavelength band may be irradiated to thegerminated seed at a dose of about 50 μmol/m²s to about 300 μmol/m²s. Inaddition, for some crops, the light in the first wavelength band may beirradiated to the germinated seed at a dose of about 50 μmol/m²s toabout 70 μmol/m²s.

When the dose of the light in the first wavelength band is less thanabout 50 μmol/m²s, a chlorophyll production and a photosynthesis due tothe light in the first wavelength band do not occur sufficiently, andthus the plant growth may be delayed. On the contrary, when the dose ofthe light in the first wavelength band exceeds about 300 μmol/m²s thatis a light saturation point, the plant may be dried because the plant isirradiated with an amount of light more than an amount that the plantneeds. However, the light saturation point may vary for every crop andgrowth stage. For example, in the case of the seedling of the Fabaceaefamily plant and the Poaceae family plant, the light saturation pointmay be about 70 μmol/m²s. Accordingly, the light in the first wavelengthband may be irradiated at the dose of about 50 μmol/m²s to about 70μmol/m²s.

The second time during which the light in the first wavelength band isirradiated may vary depending on the type of plant. Accordingly, theuser or the controller may control the second time differently dependingon the type of plant that is to be cultivated.

Then, the light in the second wavelength band is irradiated to the plantgrown from the seed (S300).

The light in the second wavelength band may be irradiated to the plantduring the third time. As the light in the second wavelength band isirradiated to the plant, the total phenolic compound content mayincrease in the plant.

The light in the second wavelength band may be irradiated to the plantgrown from the seed during the third time right before harvesting theplant. Accordingly, the plant may receive the light for the third timecalculating backward from the point of harvest, and thus a secondarymetabolism in the plant may be promoted and the total phenolic compoundcontent may increase.

The light in the second wavelength band may be irradiated to the seed orthe plant at a dose of about 5 μW/cm² to about 15 μW/cm². As the lightin the second wavelength band is irradiated to the plant at theabove-mentioned dose, only the phenolic compound content may increasewithout causing damages and modifications of plant cells. For example,when the light is irradiated to the seed or the plant at the dose lessthan about 5 μW/cm², a stress applied to the plant cells isinsufficient, and as a result, a hormesis response for the production ofantioxidant may not be induced sufficiently. On the other hand, when thelight is irradiated to the seed or the plant at the dose exceeding about15 μW/cm², the plant cells may be damaged or modified.

An intensity of the light in the second wavelength band is not uniformin all wavelength bands. According to the type of plant, the intensityof the light in a specific wavelength band of the light having awavelength of about 200 nm to about 400 nm may increase. For example, inthe case where the plant is wheat, the intensity of the light having thewavelength of about 295 nm may increase among the wavelength band ofabout 200 nm to about 400 nm. Therefore, it is possible to irradiate thelights customized to each type of plant, and the total phenolic compoundcontent in the plant may be maximized.

According to the exemplary embodiment, the seeds of the plant may besequentially germinated and grown, and the secondary metabolism in theplant may be promoted. Thus, the plants with a high total phenoliccompound content and a high antioxidant capacity may be obtained fromcommercially available seeds.

In the above descriptions, the plant cultivation method according to theexemplary embodiment of the present disclosure is schematicallydescribed. According to the exemplary embodiment, the plants may beautomatically cultivated without the user's operation, and hereinafter,the method for cultivating the plant without the user's operation willbe described in more detail.

FIG. 8 is a flowchart showing a plant cultivation method according to anexemplary embodiment of the present disclosure.

According to the exemplary embodiment of the present disclosure, theplant cultivation device is operated by the controller, and thecontroller cultivates the plant according to the plant cultivationmethod according to the exemplary embodiment of the present disclosurewithout the user's involvement.

First, when the seed is provided in the plant cultivation device, thecontroller maintains the seed in a germination condition from a firsttime point T1 (S101). The first time point T1 may be a time point atwhich the seed is put into the plant cultivation device according to theexemplary embodiment of the present disclosure and the user performs anoperation to start the cultivation. For example, the operation to startthe cultivation may be an action that turns on the plant cultivationdevice and pushes a button for starting the cultivation.

As described above, since the germination condition of the plant maydiffer depending on the type of plant, the controller may read out thegermination condition suitable for the type of plant from a database andmay apply the read-out germination condition.

Then, the controller compares the first time P1 with a differencebetween a current time T and the first time point T1, i.e., the elapsedtime from the first time point T1 to the current time T (S102). Thefirst time P1 is the time required for germinating the plant, and thecontroller determines that the germination of the seed is completed whenthe first time P1 elapses from the first time point T1.

As described above, since the first time P1 may vary depending on thetype of plant, the controller may set the first time P1 differentlydepending on the type of plant. For example, when the plant is theFabaceae family plant, or the Poaceae family plant, the first time P1may be about 72 hours.

Then, when the difference between the current time T and the first timepoint T1 is equal to or greater than the first time P1, the controllerallows the light in the first wavelength band to be irradiated to theseed (S201). In this case, a time point at which the controller controlsthe first light source to irradiate the light in the first wavelengthband is a second time point T2. On the other hand, when the differencebetween the current time T and the first time point T1 is smaller thanthe first time P1, the controller maintains the inside of the plantcultivation device to be in the germination condition.

As described above, the light in the first wavelength band may be thevisible light wavelength band and may include the near-infraredwavelength band depending on circumstances. As the light in the firstwavelength band is irradiated, the plant may be grown from thegerminated seed. Accordingly, the light in the first wavelength band maybe controlled by taking into account the type of plant to increase agrowth rate of the plant. The controller may read out information aboutthe first wavelength band, which match with the type of plant, from thedatabase and may control the first light source based on the read-outinformation.

The controller may control the first wavelength band and the amount oflight irradiated by the first light source differently over time. Forexample, the first wavelength band and the amount of light in an initialstage of the growth of the plant, which is when the first light sourcestarts to irradiate the light, may be different from the firstwavelength band and the amount of light in a stage at which the growthof the plant is completed. Accordingly, the optimized light may beirradiated depending on the growth stage of the plant.

It is not necessary to continuously irradiate the light in the firstwavelength band during the second time P2. The controller may controlON/OFF of the first light source during the second time P2. Therefore,an internal environment of the plant cultivation device may be set as anatural environment where the sun rises and falls. For example, in thesecond time P2, a ratio of a time during which the first light sourceemits the light in the first wavelength band to a time during which thefirst light source does not emit the light in the first wavelength bandis about 1:1 to about 2:1. Thus, the environment similar to the naturalenvironment where the sun rises and sets regularly everyday may be setin the plant cultivation device. As the environment similar to thenatural environment is set, both photosynthesis and respiration of theplant may be maintained well balanced within the plant cultivationdevice.

Then, the controller determines whether a difference between the currenttime T and the second time point T2, i.e., the elapsed time from thesecond time point T2 to the current time T, is equal to or greater thanthe second time P2 (S202). The second time P2 is the time required forgrowing the plant, and the controller determines that the plant is notgrown to a desired level unless the second time P2 elapses. However, thesecond time P2 is not the time required for the plant to grow fully. Forexample, when the plant is planned to be harvested at its sprout stage,the second time P2 may be the time required for the germinated seed togrow to the sprout.

The second time P2 may vary depending on the type of plant, and thecontroller may read out the second time P2 suitable for the type ofplant from a database and may apply the read-out second time P2.

Then, when the difference between the current time T and the second timepoint T2 is equal or greater than the second time P2, the controllerallows the second light source to irradiate the light in the secondwavelength band to the seed (S301). In this case, a time point at whichthe controller controls the second light source to irradiate the lightin the second wavelength band is a third time point T3. On the otherhand, when the difference between the current time T and the second timepoint T2 is smaller than the second time P2, the controller controls thefirst light source to continuously irradiate the light in the firstwavelength band.

As described above, the second wavelength band may be within the rangefrom about 200 nm to about 400 nm. As the above-mentioned light isirradiated, the secondary metabolism of the plant may be activated andthe total phenolic compound content in the plant may increase.

Then, the controller determines whether a difference between the currenttime T and the third time point T3, i.e., the elapsed time from thethird time point T3 to the current time T, is equal to or greater thanthe third time P3 (S302). When the elapsed time from the third timepoint T3 to the current time T is equal or greater than the third timeP3, the controller stops the emission of the light in the secondwavelength band from the second light source. On the contrary, when theelapsed time from the third time point T3 to the current time T issmaller than the third time P3, the controller controls the second lightsource to continuously emit the light in the second wavelength band.

The third time P3 may be equal to or smaller than about 48 hours. In acase where the third time P3 exceeds about 48 hours, excessive stressmore than needed is applied on the plant, and as a result, the plantcells are deformed or the plant is dried out. As the controller controlsthe second light source to irradiate the light only during the thirdtime P3, the above-mentioned problem may not occur.

The intensity of the light emitted by the second light source during thethird time P3 may be different for each wavelength. According to thetype of plant, the intensity of the light in the specific wavelengthband of the light having the wavelength of about 200 nm to about 400 nmmay increase by the controller. Therefore, it is possible to irradiatethe light customized to each type of plant, and the total phenoliccompound content in the plant may be maximized.

Since the third time P3 is provided right before the harvest of theplant, the secondary metabolism activity of the plant may be achieved bythe light in the second wavelength band after the plant has grown to thedesired stage. Accordingly, the possibility that the plant growth isinhibited by the light irradiation in the second wavelength band may bereduced.

Then, the plant is harvested (S303). In this case, a harvesting devicemay be used, and the harvesting device isolates the plant from waterafter the third time P3 elapses. Accordingly, the plant may be preventedfrom growing excessively more than intended or needed. The harvestedplant may be transferred to a separate space within the plantcultivation device by the harvesting device. Therefore, the harvestedplant may be prevented from overgrowing or from being transformed byreceiving the light in the second wavelength band after being harvested.

According to the exemplary embodiment of the present disclosure, theplant having a high total phenolic compound content may be cultivatedaccording to a predetermined reference even though the user is notinvolved in the growing process. Thus, users who are not familiar withthe plant cultivation may easily grow and harvest the plant with a hightotal phenolic compound content.

In the above descriptions, the plant cultivation device and the plantcultivation method, which are used to cultivate the plant with a hightotal phenolic compound content, are described. Hereinafter, the totalphenolic compound content and the antioxidant capacity of the plant,which are obtained by the plant cultivation device and the plantcultivation method according to the exemplary embodiment of the presentdisclosure, will be described in detail with reference to data.

The following Tables 1A to 1E show that plants were grown by differentlyirradiating the light in the second wavelength band (about 275 nm, about295 nm) on the Fabaceae family plant and the Poaceae family plant. Plantcultivation conditions are as follows.

TABLE 1A Mung bean (Fabaceae family) Comparative Embodiment Embodimentexample 1A example 1A example 2A Light in X 295 nm 275 nm secondwavelength band

TABLE 1B Pea (Fabaceae family) Comparative Embodiment Embodiment example1B example 1B example 2B Light in second X 295 nm 275 nm wavelength band

TABLE 1C Alfalfa (Fabaceae family) Comparative Embodiment Embodimentexample 1C example 1C example 2C Light in second X 295 nm 275 nmwavelength band

TABLE 1D Wheat (Poaceae family) Comparative Embodiment Embodimentexample 1D example 1D example 2D Light in second X 295 nm 275 nmwavelength band

TABLE 1E Barley (Poaceae family) Comparative Embodiment Embodimentexample 1E example 1E example 2E Light in second X 295 nm 275 nmwavelength band

The plant cultivation conditions are the same in both the Embodimentexample and the Comparative example except that whether the light in thesecond wavelength band was irradiated. The plants of the Embodimentexample and the Comparative example were germinated in the dark roomcondition during about 72 hours and were grown using a white lightemitting diode light source during about 144 hours. The white lightemitting diode light source was controlled with a ratio of an operatingtime to a non-operating time of 2:1 in about 144 hours. That is, theplants were grown for about 144 hours by repeating operations of turningon the white light emitting diode for about 16 hours in 24 hours andturning off the white light emitting diode for about 8 hours in 24hours. The light was irradiated at a dose of about 60 μmol/m²s by thewhite light emitting diode during operation. The inside of the plantcultivation device was maintained at a temperature of about 24° C. and arelative humidity of about 70±5%.

In addition, the plants of the Embodiment examples were irradiated withthe light in the second wavelength band during about 24 hours rightbefore the harvest. The light in the second wavelength band wasirradiated at a dose of about 10 μW/cm². The plants of the Comparativeexample is not irradiated with the light in the second wavelength band.

The following Tables 2A to 2E show the measured total phenolic compoundcontent contained in the plants of the Embodiment examples and theComparative examples. Experiments were conducted to determine how muchthe total phenolic compound content contained in Embodiment examples 1Ato 1E and Embodiment examples 2A to 2E was increased in comparison withComparative examples 1A to 1E.

TABLE 2A Mung bean (Fabaceae family) Comparative Embodiment Embodimentexample 1A example 1A example 2A Increase/decrease 100% 94.7% 109.8%rate in total phenolic compound content (%)

TABLE 2B Pea (Fabaceae family) Comparative Embodiment Embodiment example1B example1B example2B Increase/decrease 100% 112.7% 118.9% rate intotal phenolic compound content (%)

TABLE 2C Alfalfa (Fabaceae family) Comparative Embodiment Embodimentexample 1C example 1C example 2C Increase/decrease 100% 118.6% 119.0%rate in total phenolic compound content (A)

TABLE 2D Wheat (Poaceae family) Comparative Embodiment Embodimentexample 1D example 1D example 2D Increase/decrease 100% 126.0% 121.6%rate in total phenolic compound content (A)

TABLE 2E Barley (Poaceae family) Comparative Embodiment Embodimentexample 1E example 1E example 2E Increase/decrease 100% 125.7% 133.9%rate in total phenolic compound content (%)

Referring to Tables 2A to 2E, it was confirmed that the total phenoliccompound content in the plants was generally increased in Embodimentexamples 1A to 1E and Embodiment examples 2A to 2E as compared withComparative examples 1A to 1E in which the light in the secondwavelength band was not irradiated.

In the case of mung bean, as compared with Comparative example 1A inwhich the light in the second wavelength band was not irradiated, it wasconfirmed that the total phenolic compound content was increased byabout 9.8% in Embodiment example 2A to which the light having thewavelength of about 275 nm was irradiated.

In the case of pea, as compared with Comparative example 1B in which thelight in the second wavelength band was not irradiated, it was confirmedthat the total phenolic compound content was increased by about 12.7% inEmbodiment example 1B to which the light having the wavelength of about295 nm was irradiated, and it was confirmed that the total phenoliccompound content was increased by about 18.9% in Embodiment example 2Bto which the light having the wavelength of about 275 nm was irradiated.

In the case of alfalfa, as compared with Comparative example 1C in whichthe light in the second wavelength band was not irradiated, it wasconfirmed that the total phenolic compound content was increased byabout 18.6% in Embodiment example 1C to which the light having thewavelength of about 295 nm was irradiated, and it was confirmed that thetotal phenolic compound content was increased by about 19.0% inEmbodiment example 2C to which the light having the wavelength of about275 nm was irradiated.

In the case of wheat, as compared with Comparative example 1D in whichthe light in the second wavelength band was not irradiated, it wasconfirmed that the total phenolic compound content was increased byabout 26.0% in Embodiment example 1D to which the light having thewavelength of about 295 nm was irradiated, and it was confirmed that thetotal phenolic compound content was increased by about 21.6% inEmbodiment example 2D to which the light having the wavelength of about275 nm was irradiated.

In the case of barley, as compared with Comparative example 1E in whichthe light in the second wavelength band was not irradiated, it wasconfirmed that the total phenolic compound content was increased byabout 25.7% in Embodiment example 1E to which the light having thewavelength of about 295 nm was irradiated, and it was confirmed that thetotal phenolic compound content was increased by about 33.9% inEmbodiment example 2E to which the light having the wavelength of about275 nm was irradiated.

Accordingly, it was confirmed that the total phenolic compound contentwas significantly increased in the Fabaceae family plant and the Poaceaefamily plant when the Fabaceae family plant and the Poaceae family plantwere irradiated with the light in the second wavelength band. Inparticular, in the case of Embodiment example 2A, Embodiment example 1B,Embodiment example 2B, Embodiment example 1C, Embodiment example 2C,Embodiment example 1E, and Embodiment example 2E, a statisticallysignificant increase in the total phenolic compound content wasconfirmed.

Then, tests for measuring the antioxidant capacity were conducted toconfirm whether the difference in the total phenolic compound contentcauses differences in the actual antioxidant capacity. The antioxidantcapacity was measured by an ABTS assay using ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid]. The blue ABTS radical cationis reactive towards antioxidants and is converted back to its colorlessneutral form. As the antioxidant content increases, the amount of ABTSradical cation, which is converted back to its colorless neutral form,increases, and the blue color of the ABTS becomes faded. Accordingly,the antioxidant capacity was measured against antioxidant capacity ofTrolox that is an antioxidant substance by spectrophotometricallyanalyzing a color change of an ABTS solution after a plant extract ofEmbodiment examples and Comparative examples was reacted with the ABTSsolution.

The following Tables 3A to 3E show the measured antioxidant capacity ofthe plants of the Embodiment examples and the Comparative examples.Experiments were conducted to determine how much the antioxidantcapacity of Embodiment examples 1A to 1E and Embodiment examples 2A to2E was increased in comparison with Comparative examples 1A to 1E.

TABLE 3A Mung bean (Fabaceae family) Comparative Embodiment Embodimentexample 1A example 1A example 2A Increase/decrease of antioxidantcapacity (%) 100% 120.6% 134.5%

TABLE 3B Pea (Fabaceae family) Comparative Embodiment Embodiment example1B example 1B example 2B Increase/decrease of antioxidant capacity (%)100% 120.8% 123.4%

TABLE 3C Alfalfa (Fabaceae family) Comparative Embodiment Embodimentexample 1C example 1C example 2C Increase/decrease of antioxidantcapacity (%) 100% 99.2% 99.9%

TBLE 3D Wheat (Poaceae family) Comparative Embodiment Embodiment example1D example 1D example 2D Increase/decrease of antioxidant capacity (%)100% 132.7% 139.5%

TABLE 3E Barley (Poaceae family) Comparative Embodiment Embodimentexample 1E example 1E example 2E Increase/decrease of antioxidantcapacity (%) 100% 146.2% 146.2%

In the case of mung bean, as compared with Comparative example 1A inwhich the light in the second wavelength band was not irradiated, it wasconfirmed that the antioxidant capacity was increased by about 20.6% inEmbodiment example 1A to which the light having the wavelength of about295 nm was irradiated, and it was confirmed that the antioxidantcapacity was increased by about 34.5% in Embodiment example 2A to whichthe light having the wavelength of about 275 nm was irradiated.

In the case of pea, as compared with Comparative example 1B in which thelight in the second wavelength band was not irradiated, it was confirmedthat the antioxidant capacity was increased by about 20.8% in Embodimentexample 1B to which the light having the wavelength of about 295 nm wasirradiated, and it was confirmed that the antioxidant capacity wasincreased by about 23.4% in Embodiment example 2B to which the lighthaving the wavelength of about 275 nm was irradiated.

In the case of alfalfa, when comparing Comparative example 1C in whichthe light in the second wavelength band was not irradiated withEmbodiment examples 1C and 2C, it was confirmed that there was nosubstantial change in the antioxidant capacity.

In the case of wheat, as compared with Comparative example 1D in whichthe light in the second wavelength band was not irradiated, it wasconfirmed that the antioxidant capacity was increased by about 32.7% inEmbodiment example 1D to which the light having the wavelength of about295 nm was irradiated, and it was confirmed that the antioxidantcapacity was increased by about 39.5% in Embodiment example 2D to whichthe light having the wavelength of about 275 nm was irradiated.

In the case of barley, as compared with Comparative example 1E in whichthe light in the second wavelength band was not irradiated, it wasconfirmed that the antioxidant capacity was increased by about 46.2% inEmbodiment example 1E to which the light having the wavelength of about295 nm was irradiated, and it was confirmed that the antioxidantcapacity was increased by about 46.2% in Embodiment example 2E to whichthe light having the wavelength of about 275 nm was irradiated.

As described above, in the case of the Fabaceae family plant and thePoaceae family plant, it has been confirmed that the total phenoliccompound content generally leads to the increase in the actualantioxidant capacity. In particular, in the case of Embodiment example1A, Embodiment example 2A, Embodiment example 1B, Embodiment example 2B,Embodiment example 1E, and Embodiment example 2E, a statisticallysignificant increase in the antioxidant capacity was confirmed.

FIG. 9 is a flowchart showing a cultivation method according to anexemplary embodiment of the present disclosure.

Referring to FIG. 9, according to another embodiment of the presentdisclosure, the cultivation method includes germinating the seeds of theplant (S11), growing the germinated seeds to the sprouts (S13),irradiating the light in the ultraviolet wavelength band to the plants(S15), and growing the sprouts of the plant to an adult plant (S17). Inthis case, the growing the sprouts of the plant means both growing thesprouts of the plant to the adult plant and growing the sprouts of theplant to a certain state before the adult plant stage. A time durationfor growing the sprouts of the plant (S17) may vary depending on thetype of plants.

The germination of the plant may be performed by putting the barleyseeds into the cultivation device according to the exemplary embodimentof the present disclosure and supplying water in a dark condition. Inthe exemplary embodiment of the present disclosure, water may besupplied to the seeds of the plant under the dark condition from about 1day to about 5 days. For example, the plant may be germinated bysupplying water to the seeds under the dark condition for about 3 days.

The seeds of the plant may be soaked and swollen with a purified waterfor a predetermined time to be germinated. This is to allow the seeds toabsorb sufficient water, and thus, the water may be supplied to theseeds in the germinating stage. Since the germination condition may varydepending on the type of plant seeds, surroundings of the seeds may beset to match the germination condition of the seeds during the firsttime. For example, in the case of dark germination seeds that do notrequire a light for their germination, the inside of the housing may bemaintained as the dark room during the first time, and thus the insideof the housing may be maintained in the dark condition when the seedsare germinated.

In the germination stage, appropriate temperature and humidity togerminate the seeds of plant may be maintained. Various temperaturecontrol units, for example, a heater and/or a cooler, may be used tomaintain the temperature around the seeds of the plant.

In the germination stage, water may be supplied to the seeds by thewater supply unit. This is because the seeds are required to absorbsufficient water for initiating cellular metabolic process and growth.Therefore, the supply of water may be concentrated in the germinationstage such that the seeds absorb enough water or the seeds are imbibed.In the present exemplary embodiment, the purified water may be supplied.

Then, the germinated seeds are grown to the sprouts, and the light inthe ultraviolet wavelength band is irradiated to the sprouts. Here, theoperation of irradiating the light in the ultraviolet wavelength bandmay be performed together with the operation of growing the seeds to thesprouts. This is explained as follows.

To grow the germinated seeds into the plants, the dark condition orlighting condition, or the dark or lighting condition may be repeated.In the exemplary embodiment of the present disclosure, the lightingcondition may be maintained during the first time, the dark conditionmay be maintained during the second time, and the lighting condition andthe dark condition may be repeatedly performed. In other words, thesecond time during which the light in the first wavelength band isirradiated may be continuous, but the second time may have a light cyclein which lighting and darkness are repeated. In this case, the lightingcondition is maintained for a predetermined time, and the dark conditionis maintained for another predetermined time. The lighting condition andthe dark condition may be repeated a predetermined number of times on a24-hour basis in general. For example, on the 24-hour basis, thelighting condition may be maintained for about 14 hours to about 18hours, and the dark condition may be repeated within about 6 hours toabout 10 hours. In the exemplary embodiment of the present disclosure,the light cycle may include the lighting condition of about 16 hours andthe dark condition of about 8 hours, which are repeated on the 24-hourbasis, and the light cycle may be repeated for about 4 days to about 10days. In the exemplary embodiment of the present disclosure, thelighting condition may be maintained for about 16 hours, the darkcondition may be maintained for about 8 hours, and the light and darkconditions may be repeated for about 7 days.

In the exemplary embodiment of the present disclosure, both the firstlight source and the second light source are maintained in a turn-offstate during the dark condition, and the first light source ismaintained in a turn-on state during the lighting condition. During thelighting condition, the first light may be irradiated to the sprouts ofthe plant at a dose of about 60 μmol/m²s, and the second light may beirradiated at an energy of about 10 μW/cm². The dose of the first lightis to induce the photosynthesis and the growth of the plant sprouts.

In the present exemplary embodiment, the second light source may bemaintained at a constant dose in a turn-on state for a certain period oftime during the first time under the lighting condition. The secondlight source may emit the light for a time duration that is equal to orsmaller than that of the first light source when the first light sourceis turned on. Alternatively, the second light source may be repeatedlyturned on and off for a predetermined time as a predetermined pattern.In other words, the second light source may periodically emit the lightwhen the first light source is turned on. In the present exemplaryembodiment, the irradiation period of the second light source may beconfigured in various ways and may have a repetitive pattern in whichthe turn-on and the turn-off are set for a predetermined time. Theirradiation of the second light may be continuous, however, although theirradiation of the second light is maintained without interruption, thesecond light may be irradiated no more than 7 days.

However, the dose of the second light source is limited to a dose thatdoes not damage the plant. For example, in the exemplary embodiment ofthe present disclosure, the second light source may irradiate the lightat a maximum dose of about 13.44 kJ/m²s. The second light source mayprovide a light to the plant at a dose of about 1.08 kJ/m²s or more sothat a sufficient antioxidants may be produced in the plant.

Then, plant may be grown into the adult plant. In this case, theirradiation of the second light, that is, the irradiation of theultraviolet light may be carried out within a period of time from afterthe seeds are germinated until the seeds become the adult plants.However, the present disclosure should not be limited thereto orthereby.

In the exemplary embodiment of the present disclosure, the cultivatingof the sprout to the adult plant may be omitted, and the sprout withhigh antioxidant compounds content may be harvested before the sproutgrows into the adult plant.

Through the above-described method, the plants with the increasedcontent of antioxidant may be obtained. In particular, the Poaceaefamily plant with the increased antioxidant content may be obtainedthrough the above-described method. Accordingly, since the Poaceaefamily plant itself contains a large amount of antioxidants, theimmunity of the Poaceae family plant increases, and a high-quality plantthat is resistant to bacteria and microorganisms may be obtained. Asinfections with bacteria or microorganisms are less likely occur,formulation cost, product degradation, environmental pollution, andexposure of workers to risks, which arise from the spraying ofpesticides may be reduced. Further, when the Poaceae family plant isingested by humans, it may be helpful in preventing aging of cells inthe human body since its antioxidant content is high. For example, thebarley sprouts having a high antioxidant content may be ingested byhumans after being harvested, or may be ingested by humans after furtherprocessing for an ingredient for various food items.

In the case of cultivating the Poaceae family sprouts by theabove-mentioned method, the antioxidant content increases in the Poaceaefamily sprouts.

Experimental Example 1. Method of Determining a Total AntioxidantContent

The determination of the total antioxidant content was carried out inthe form of checking the total phenolic compound content.

To determine the total phenolic compound content, the barley sproutswere first lyophilized and then pulverized after being collected amongthe Poaceae family plants. The pulverized sample was dipped into about0.09 g of deionized water and about 8 mL of 80% acetone, mixed well, andapplied with an ultrasonic treatment for about 15 minutes. Then, thesample was kept at about −20° C./dark condition for about 12 hours orlonger to be extracted. The extracted sample was placed in a centrifuge(RCF 3000/RPM 1350) and centrifuged for about 2 minutes, and then, about135 μL of distilled water, about 750 μL of about 10% Folin-Ciocalteureagent, about 50 μL of sample, and about 600 μL of about 7.5% Na2CO3were added in sequence to a new test tube. Then, after mixing well forabout 10 seconds, they were allowed to react in a constant temperaturewater bath at about 45° C. for about 15 minutes and then cooledsufficiently. After that, about 1 mL of the sufficiently cooled samplewas transferred into a cuvette, and an absorbance was measured at about765 nm by using a spectrophotometer. In this case, a solution of0.4/0.35/0.3/0.25/0.2/0.15/0.1/0.05 mg/ml of gallic acid was prepared bydiluting about 1 mg/mL of gallic acid, and its absorbance was measuredto generate a standard curve, and thus the total phenolic compoundcontent was measured.

Experimental Example 2. The Increase in the Antioxidant ContentDepending on the Wavelength of the Second Light

To determine the increase in the antioxidant content of the Poaceaefamily plants depending on the wavelength of the second light, the seedsof barley, which is a member of the Poaceae family plants, wereprepared, and the barley seeds were germinated under the dark condition.The dark condition was maintained for about 3 days for the germinationof the barley seeds. Then, on a 24-hour basis, the lighting conditionwas set to about 16 hours, the dark condition was set to about 8 hours,and the lighting condition and the dark condition were repeated forabout 7 days. In this case, both the first and second lights were turnedoff during the dark condition, and the first light was turned on duringthe lighting condition. In the experimental example, during the lightingcondition, the second light had peak wavelengths of about 275 nm, about285 nm, and about 295 nm and was periodically repeatedly turned on andoff. The cases where the light sources respectively having the peakwavelengths of about 275 nm, about 285 nm, and about 295 nm were used asthe second light correspond to the first to third embodiment examples,and the case where the second light was not applied corresponds to aComparative example. In the present experimental example, theComparative example and Embodiment examples 1 to 3 were carried out inthe same conditions except for the applied wavelength.

FIG. 10 is a graph showing a phenolic compound content as a function ofa wavelength of a second light. Referring to FIG. 10, the phenoliccompound content was remarkably increased in all of Embodiment examples1 to 3 as compared with the Comparative example. That is, the totalphenolic compound content was increased by about 20% or more in all ofEmbodiment examples 1 to 3 in comparison with the Comparative example.In particular, the phenolic compound content in Embodiment example 2 wasremarkably increased than those observed in Embodiment examples 1 and 3as compared with a control group. In detail, in the case where thesecond light has the peak wavelengths of about 275 nm and 295 nm, thetotal phenolic compound content was increased by about 23% as comparedwith the Comparative example, and in the case where the second light hasthe peak wavelength of about 285 nm, the total phenolic compound contentwas increased by about 38% as compared with the Comparative example.

As a result, it was found that the total phenolic compound content wasremarkably increased through the irradiation of the second light, and itwas found that the total phenolic compound content was remarkablyincreased by irradiation of the second light having the peak wavelengthof about 285 nm.

Experimental Example 3. Damage of Barley Sprouts Depending on theUltraviolet Dose

When the second light was the light having the peak wavelength of about285 nm, it was observed whether or not the barley sprouts were damageddue to the dose so as to determine a range of the effective dose.

FIG. 11 are photographs of the barley sprouts after the second lighthaving the peak wavelength at about 285 nm is applied to the barleysprouts with different doses under the same condition as in experimentalexample 2. The numerical values shown in the photographs of FIG. 11indicate the dose of the second light applied to the barley sprouts.

Referring to FIG. 11, in a case where the applied amount of the secondlight was about 13.44 kJ/m²s or less, no apparent difference was foundas compared with a case where the second light was not applied to thebarley sprouts. As a result, it was found that the barley sprouts werehardly affected by the application of the second light when the appliedamount of the second light was about 13.44 kJ/m²s or less. However, in acase where the applied amount of the second light was about 15.12 kJ/m²sor more, it was found that each leaf of the barley sprouts was witheredfrom the end thereof and was turned yellow.

As a result, it was found that the second light needs to be applied atthe dose of about 14 kJ/m²s or less.

Experimental Example 4. Total Antioxidant Content in the Barley SproutsDepending on the Dose of the Ultraviolet Light

FIG. 12 is a graph showing the total phenolic compound content in thebarley sprouts after the second light having the peak wavelength at 285nm is applied to the barley sprouts with different doses under the samecondition as in experimental example 2. In FIG. 12, since the damagecaused by the second light, such as withering of the barley sprouts,occurs when the dose exceeds about 14 kJ/m²s as in experimental Example3, only the cases where the dose was about 14 kJ/m²s or less are shownexcept the case where the dose is exceeded about 14 kJ/m²s.

Referring to FIG. 12, in the cases where the applied amount of thesecond light was about 14 kJ/m²s or less, the total phenolic compoundcontent was increased in all the cases as compared with the Comparativeexample. In addition, in the cases where the applied amount of thesecond light was about 3 kJ/m²s or more and about 14 kJ/m²s or less, thetotal phenolic compound content was remarkably increased in all thecases as compared with the Comparative example. In particular, in thecase where the second light was applied to the barley sprouts at a doseof about 8.64 kJ/m²s, the total phenolic compound content was muchhigher than that of the Comparative example.

Experimental Example 5. Damage of Wheat Sprouts Depending on theUltraviolet Dose

When the second light was the light having the peak wavelength of about285 nm, it was observed whether or not the wheat sprouts were damageddue to the dose so as to determine a range of the effective dose.

FIG. 13 are photographs of the wheat sprouts after the second lighthaving the peak wavelength at about 285 nm is applied to the wheatsprouts with different doses under the same condition as in experimentalexample 2. The numerical values shown in the photographs of FIG. 13indicate the dose of the second light applied to the wheat sprouts.

Referring to FIG. 13, in a case where the applied amount of the secondlight was about 13.4 kJ/m²s or less, no difference in appearance wasfound as compared with a case where the second light was not applied tothe wheat sprouts. As a result, it was found that the wheat sprouts werehardly affected by the application of the second light when the appliedamount of the second light was about 13.4 kJ/m²s or less. As a result,it was found that the second light needs to be applied at the dose ofabout 13.4 kJ/m²s or less.

Experimental Example 6. Total Antioxidant Content in the Wheat SproutsDepending on the Dose of the Ultraviolet Light

FIG. 14 is a graph showing the total phenolic compound content in thewheat sprouts after the second light having the peak wavelength at 285nm is applied to the wheat sprouts with different doses under the samecondition as in experimental example 2. In FIG. 14, since the damagecaused by the second light, such as withering of the wheat sprouts,occurs when the dose exceeds about 13.4 kJ/m²s as in experimentalExample 5, only the cases where the dose was about 13.4 kJ/m²s or lessare shown except the case where the dose exceeds about 13.4 kJ/m²s.

Referring to FIG. 14, in the cases where the cumulative applied amountof the second light over a day was about 2.02 kJ/m² or less, thephenolic compound content was not increased in the wheat sprouts. Indetail, it was found that the phenolic compound content in the wheatsprouts are about 13 mg/gDW in both cases where the wheat sprouts arenot irradiated and the wheat sprouts are irradiated with the secondlight by about 2.02 kj/m2 over a day.

In the cases where the cumulative applied amount of the second lightover a day exceeds about 13.4 kJ/m², it was found that the phenoliccompound content was decreased in the wheat sprouts. In detail, in thecases where the second light was applied to the wheat sprouts over a dayby about 13.4 kJ/m², it was found that the phenolic compound content inthe wheat sprouts was about 14 mg/g DW. This was smaller than thephenolic compound content in the wheat sprouts obtained when the secondlight was applied to the wheat sprouts over a day by about 4.03 kJ/m² orabout 8.06 kJ/m².

The above-described trend suggests that the cumulative amount of UVirradiation may be required to be equal to or greater than a thresholdvalue so as to increase the amount of the secondary metabolites in thewheat sprouts by the UV irradiation. In addition, as the cumulativeamount of UV irradiation increases, the sprouts are damaged by the UV.Accordingly, when the cumulative amount of UV irradiation is equal to orgreater than a certain level, it suggests that useful substancesincluding the phenolic compounds in the sprouts may be destroyed by theUV.

Therefore, it is preferred that the cumulative applied amount of thesecond light over a day is set to a range between about 4.03 kJ/m² andabout 13.4 kJ/m² so as to increase the total phenolic compound contentin the wheat sprouts.

Although the exemplary embodiments of the present disclosure have beendescribed, it is understood that the present disclosure should not belimited to these exemplary embodiments but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present disclosure as hereinafter claimed.

Therefore, the disclosed subject matter should not be limited to anysingle embodiment described herein, and the scope of the presentinventive concept shall be determined according to the attached claims.

What is claimed is:
 1. A plant cultivation light source unit,comprising: a substrate; and a first group of light sources comprising aplurality of light sources disposed on the substrate, a light sourcecomprising a light emitting structure including a first semiconductorlayer, an active layer, and a second semiconductor layer; wherein theplurality of light sources operates to emit lights having differentwavelength bands and comprises: a first light source that emits firstlight having an area of at least about 55% compared with an area of anormalized solar spectrum; a second light source that emits second lighthaving a wavelength for cryptochrome; and a third light source thatemits third light having a wavelength for phytochrome.
 2. The plantcultivation light source unit of claim 1, wherein the first light sourceincludes a peak having a deviation equal to or smaller than about 0.14compared with the normalized solar spectrum.
 3. The plant cultivationlight source unit of claim 1, further comprising a second group of lightsources that have a wavelength band between 200 nm and 400 nm.
 4. Theplant cultivation light source unit of claim 1, further comprises acontroller coupled to the plurality of light sources in the first groupof light sources and controlling a lighting condition and a darkcondition, wherein the first group of light sources is turned off duringthe dark condition.
 5. The plant cultivation light source unit of claim4, wherein a ratio of the lighting condition to the dark condition is1:1 to 2:1
 6. The plant cultivation light source unit of claim 1,wherein the plurality of light sources in the first group of lightsources further comprises an IR light source.
 7. The plant cultivationlight source unit of claim 1, wherein the plurality of light sourcesfurther comprises a white light emitting diode light source whichirradiates at a dose of about 60 μmol/m²s.
 8. The plant cultivationlight source unit of claim 3, wherein the second group of light sourcesis turned on or off such that a dose of the light is equal to or greaterthan about 1 kJ/m²s and equal to or smaller than about 14 kJ/m²s.
 9. Theplant cultivation light source unit of claim 4, further comprising asecond group of light sources that have a wavelength band of between 200nm to 400 nm; and the controller is further configured to control thesecond group of light sources to irradiate light to a selected plant fora predetermined number of hours prior to harvesting of the selectedplant.
 10. The plant cultivation light source unit of claim 1, wherein aplant includes a Fabaceae Family plant, or a Poaceae Family plant.
 11. Aplant cultivation device, comprising: a plant cultivation light sourceunit; a housing that houses a plant and the plant cultivation lightsource unit installed therein; and a controller that controls the plantcultivation light source unit; wherein the plant cultivation lightsource unit comprises: a substrate; and a first group of light sourcescomprising a plurality of light sources disposed on the substrate, alight source comprising a light emitting structure including a firstsemiconductor layer, an active layer, and a second semiconductor layer;wherein the plurality of light sources operates to emit lights havingdifferent wavelength bands and comprises: a first light source thatemits first light having an area of at least about 55% compared with anarea of a normalized solar spectrum; a second light source that emitssecond light having a wavelength for cryptochrome; and a third lightsource that emits third light having a wavelength for phytochrome. 12.The plant cultivation device of claim 11, wherein the first light sourcecomprises a peak having a deviation equal to or smaller than about 0.14compared with the normalized solar spectrum.
 13. The plant cultivationdevice of claim 11, wherein the plant cultivation light source unitfurther comprises a second group of light sources that have a wavelengthband between 200 nm and 400 nm.
 14. The plant cultivation device ofclaim 11, wherein the controller is coupled to the plurality of lightsources in the first group of light sources and controlling a lightingcondition and a dark condition, wherein the first group of light sourcesis turned off during the dark condition.
 15. The plant cultivationdevice of claim 14, wherein a ratio of the lighting condition to thedark condition is 1:1 to 2:1
 16. The plant cultivation device of claim11, wherein the plurality of light sources in the first group of lightsources further comprises an IR light source.
 17. The plant cultivationdevice of claim 11, wherein the plurality of light sources furthercomprises a white light emitting diode light source which irradiates ata dose of about 60 μmol/m²s.
 18. The plant cultivation device of claim13, wherein the second group of light sources is turned on or off suchthat a dose of light is equal to or greater than about 1 kJ/m²s andequal to or smaller than about 14 kJ/m²s.
 19. The plant cultivationdevice of claim 14, wherein the plant cultivation light source unitfurther comprises a second group of light sources that have a wavelengthband of between 200 nm to 400 nm; and the controller controls the secondgroup of light sources to irradiate light to the plant for apredetermined number of hours prior to harvesting of the plant.
 20. Theplant cultivation device of claim 11, wherein the plant includes aFabaceae Family plant, or a Poaceae Family plant.